operational safety - nucleus

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Operational Safety

Bon Hyun Koo e-mail : [email protected]

KINS-IAEA-ANNuR-ANSN-FNBRA Joint Workshop on BPTC

4-15 May, 2015, Tunis, Tunisia

Operational Safety

OEF Tools

Safety Requirements for Operation

Operating Experience Feedback

Accidents V

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Status and Issues in Nuclear Safety Regulation

I. Operational Safety

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Safety

Safety Safety is a condition or a state with no risk or no

concern with an accident.(Korean Dictionary)

Constituents of Nuclear Safety Hardware

Software

Human Factor(Safety Culture, Management System)

Meaning of Safety 'Safety' is the achievement of proper operating

conditions, prevention of accidents and mitigation of

accident consequences, resulting in protection of

workers, the public and the environment from undue

radiation hazards. (IAEA Safety Glossary)

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Safety

NPP Safety shall be ensured by means of the

followings; proper SITING, DESIGN, CONSTRUCTION and

COMMISSIOING,

followed by the proper MANAGEMENT and OPERATION.

in a later phase, proper DECOMMISSIONING is required

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Safety Analysis Report

SAR(Safety Analysis Report) is the basic Licensee

documents and is based on specific safety

analysis and shall be submitted to the Regulatory

Body for authorization

Licensee describes the results of safety analysis in

the SAR based on approved experiments,

approved analysis codes or Industrial Code & Std.

Regulatory Body should verify the conservatism

and safety margin contained in the SAR based on

its own audit calculation and/or in-depth review

and inspection.

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Safety-concerned Parties

So, the SAFETY shall be maintained during normal

operation and accident condition.

Licensee shall show(substantiate) the safety of its facility

via documents, i.e. SAR, RSE, TR.

Regulatory Body shall confirms the safety via Safety

Review and Safety Inspection.

Stakeholders and NGOs are monitoring all the above

activities.

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Safety Review

RB/TSO are responsible for the review and

evaluation for the Safety of NPP and Nuclear

Facilities.(IAEA-NS-R-2 Safety of NPP: Operation) PSAR for Construction Permit (CP)

FSAR for Operating License (OL)

PSR for the next 10 year’s safe operation

RTSR (Reload Transition Safety Report) for new Fuel Loading or Steam Generator Replacement

RSE (Reload Safety Evaluation) for every reload core as the Reactor Core configuration is different for every reload core.

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Operational Safety

IAEA proposes the following 10 topics to ensure the safe operation of NPP(NS-R-2 Safety of NPP : Operation)

1) Operating Organization (including OEF) 2) Qualification and Training of Personnel 3) Commissioning Program for the Plant 4) Plant Operations: OLC/ Operating instructions and

procedures/ Core management and fuel handling 5) Maintenance, Testing, Surveillance and Inspection of

‘SSCs important to Safety’ 6) Plant Modifications 7) Radiation Protection and Radioactive Waste

Management 8) Records and Reports 9) Periodic Safety Review

10) Decommissioning

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Responsibility on NPP Safety

Licensee has the ultimate responsibility on NPP safety. May outsource some parts of NPP operation, e.g.,

maintenance. But licensee has the prime responsibility on it. Must provide the necessary resources and support

RB and TSO confirms the safety of facilities permeated in the Licensee document and all the activities performed by the Licensee.

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II. Safety Requirements for Operation

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IAEA Convention on Nuclear Safety (1)

Convention on Nuclear Safety [Art. 19. “Operation”]

(1) the initial authorization to operate a nuclear installation is based upon the

safety analysis and a commissioning program demonstrating that the

installation is consistent with design and safety requirements;

(2) operational limits and conditions(OLC) derived from the safety analysis,

tests and operational experience are defined and revised as necessary for

identifying safe boundaries for operation;

(3) operation, maintenance, inspection and testing of a nuclear installation are

conducted in accordance with approved procedures;

(4) procedures are established for responding to anticipated operational

occurrences (AOO) and to accidents;

(5) necessary engineering and technical support in all safety related fields is

available throughout the lifetime of a nuclear installation;

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Nuclear Industries in Korea

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KPS / SEC

PLANT MAINTENANCE

KAERI / KEPRI

R & D

DOOJUNG DOOSAN HEAVY INDUSTRIES CO.

MAIN EQUIPMENT SUPPLY

KOPEC KOREA POWER ENGINEERING CO.

NSSS DESIGN + A/E

ENGINEERING

KHNP

OPERATION &

CONSTRUCTION

KNFC

KOREA NUCLEAR FUEL CO.

NUCLEAR FUEL SUPPLY

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IAEA Convention on Nuclear Safety(2)

(6) incidents significant to safety are reported in a timely manner by the

licensee to the regulatory body;

(7) program to collect and analyze operating experience(OEF) are

established, the results and conclusions are acted upon and that

existing mechanisms are used to share important experience with

international bodies and with other operating organizations and

regulatory bodies;

(8) the generation of radioactive waste resulting from the operation of a

nuclear installation is kept to the minimum practicable for the

process concerned, both in activity and in volume, and any

necessary treatment and storage of spent fuel and waste directly

related to the operation and on the same site as that of the nuclear

installation take into consideration conditioning and disposal.

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IAEA NS-R-2 ‘Safety of NPP: Operation’ stipulates 10 requirements for the Operational safety;

I. Operating Organization (including OEF)

II. Qualification and Training of Personnel

III. Commissioning Program for the Plant

IV. Plant Operations: Operational limits and conditions/ Operating instructions and procedures/ Core management and fuel handling

V. Maintenance, Testing, Surveillance and Inspection of Structures, Systems and Components important to Safety

VI. Plant Modifications

VII.Radiation Protection and Radioactive Waste Management

VIII.Records and Reports

IX. Periodic Safety Review

X. Decommissioning

IAEA Safety Requirement for Operation

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Operating Organization(1)

The Operating Organization(Licensee) shall have the responsibility for the safe operation of NPP

The licensee shall consider the following management functions in establishing the organizational structure; Policy making function, Operating functions,(operation) Supporting

functions and, and Reviewing functions

The organizational structure shall be clearly structured & documented so as to ensure that the following responsibilities are discharged to achieve safe operation; Responsibilities shall be allocated and authority shall be delegated

within the organization. Adequate training for personnel shall be provided Liaison shall be established with the RB and with public authorities, with

domestic and international organization.

Safety related activities shall be performed by qualified and experienced persons and certain activities may be performed by contractors if properly qualified, approved, controlled and supervised by the plant staff.

General Requirements

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Interface with Regulatory Body

Operational safety shall be subject to surveillance by a RB

independent of the Operating Organization(licensee); there should be mutual understanding and respect between the

bodies with frank and open, but formal relationship

Licensee shall give the RB all the necessary assistance,

information and access to the plant and documentation; if required, undertake special analysis, tests and inspections

Licensee shall submit or make available documents and other

information in accordance with the legal requirements

• Licensee shall develop and implement a internal procedure for

reporting abnormal events to the RB in accordance with the

established criteria


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Feedback of Operating Experience

OE shall be evaluated in a systematic way for correct

investigation of direct and root cause, recommendation, and

proper corrective actions

Other plants OE shall be properly collected and evaluated to

derive Lessons Learned. Exchange of OE between national and

international organization is of great importance.

All plant personnel shall be required to report all events and

shall be encouraged to report any ‘near miss’ relevant to the

safety.


Fire Safety

Physical Protection

Quality Assurance

Emergency Preparedness

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Qualification and Training(1)

The operating organization shall define the qualifications and

experience necessary for personnel performing safety-related duties.

These qualifications and experience shall be approved by the

regulatory body. Persons performing certain functions important to

safety shall be required to hold a formal authorization; this may be

issued or acknowledged by the regulatory body

A suitable program shall be established and maintained for the

training of personnel before their assignment to safety related duties.

The training shall emphasize the paramount importance of safety in

all aspects of plant operation.

All personnel responsible for safety-related duties shall have

sufficient understanding of the plant and its safety features.

The training program shall include periodic confirmation of the

personnel competence and refresher training.

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Qualification and Training(2)

Performance based program shall be developed and put in place for each

major group.

Training instructor shall be technically competent

Representative simulator facilities shall be used for the training of operating

personnel

Plant staff shall receive instructions in the management of accidents beyond

the design basis. The training of operating personnel shall ensure their

familiarity with the symptoms of accidents beyond the design basis and with

the procedures for accident management.

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Specific approval by the regulatory body shall be required before

the start of normal operation. Such approval will be granted on the

basis of an appropriate safety analysis report and a commissioning

program. The commissioning program shall provide evidence that

the installation as constructed meets the design intent and complies

with the safety requirements.

A sufficient number of qualified operating personnel, at all levels

and in all areas, shall be directly involved in the commissioning

process.

To confirm the applicability and quality of the operating procedures,

they shall be verified to ensure their technical accuracy and

validated to ensure their usability with the installed equipment and

control systems, as far as possible prior to fuel loading.

Commissioning(1)

Commissioning program for the NPP

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The operating organization shall ensure that the commissioning

program includes all the tests necessary to demonstrate that the

plant as installed meets the requirements of the safety analysis

report and satisfies the design intent, and consequently can be

operated in accordance with the OLCs.

Initial fuel loading shall not be authorized until all pre-operational

tests deemed necessary by the operating organization and the

regulatory body have been performed and results acceptable to

both parties have been obtained.

Reactor criticality and initial power raising shall not be authorized

until all tests deemed necessary by the operating organization and

the regulatory body have been performed and results acceptable to

both parties have been obtained.

Commissioning(2)

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Plant operations(1)

OLC is a set of rules setting forth parameter limits, the functional

capability and the performance levels of equipment and

personnel.

The purpose of OLC is:

(1) Prevention of situations which could lead to accidents;

(2) Mitigation of the consequences of any such accidents, if they

do occur.

OLC shall be developed to ensure that the plant is operated in

accordance with the design assumptions and intent.

The OLC shall be based on an analysis of the individual plant and

its environment, in accordance with the provisions made in the

design. The necessity for each of the operational limits and

conditions shall be substantiated by a written statement of the

reason for its adoption.

Operational Limits and Conditions

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Plant operations(2)

The operational limits and conditions shall be reviewed

over the operating life of the plant in the light of

experience, developments in technology and safety, and

changes in the plant, and shall be modified if this is

required by the RB or if it is considered appropriate by

the operating organization and approved by the RB.

Plant, prior to the initial fuel loading, shall prepare the

OLC and it shall be approved by the RB before

commencement of operation.


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Plant operations(2)

The OLC is composed of; General Principles for Use & Application of TS

Definitions, Logical Connectors, Completion Times, Freq.

Safety Limits (SL) to assure the integrity of Core & RCS

Pressure, Temperature, Thermal Power

Limits on Safety System Settings

Limiting Conditions for Operation (LCO)

LCO, Applicable Modes, Actions, Surveillance Requirement.

Design Features

Site Location, Reactor Core, Fuel Storage

Administrative Controls

Organization & Responsibility, Staff Qualifications, Procedures,

Programs and Manuals, Reporting Requirements


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Typical Operational Modes


Plant operations(3)

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Operating procedures shall be developed which apply

comprehensively for normal, abnormal and emergency conditions, in

accordance with the policy of the operating organization and the

requirements of the regulatory body. Strict adherence to written

operating procedures shall be an essential element of safety policy.

It shall be ensured that operating personnel are knowledgeable of,

and have control over, the status of plant systems and equipment for

all operational states. Only designated and suitably qualified members

of the operating personnel shall control or supervise any changes in

the operational states of the plant. No other person shall interfere in

their decisions relevant to safety.

If there is a need to conduct a non-routine operation, test or

experiment, it shall be the subject of a safety review. The specific

operational limits and conditions shall be determined and a special

procedure shall be prepared.

Plant operations(4)

Operating instructions and procedures

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Procedures for General Managements; QA Procedures, Technical Admin. Procedures, Radiation Protection

for Normal operations; System Operating Procedures, General Operating Procedures, Chemistry,

Maintenance, Testing, Surveillance and Inspection…

for Abnormal & Emergency Operations; AOP, EOP

for Severe Accidents Conditions; Severe Accidents Management Guideline (SAMG)

for Emergency Preparedness; Emergency Planning

• Response to Abnormal and Emergency Operational State;

Application of appropriate procedures as far as possible.

However, Operators in some cases, should have the authority to take

corrective actions according to their judgment

(e.g., Radiation Emergency declaration during the night shift)

Plant operations(5)

Operating instructions and procedures

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The operating organization shall be responsible and shall make

arrangements for all the activities associated with core management and

on-site fuel handling in order to ensure the safe use of the fuel in the

reactor and safety in its movement and storage on the site. Provisions

shall be made to ensure that in each reactor only fuel whose design and

enrichment have been approved by the regulatory body for use with that

reactor is loaded.

Following batch refueling, tests shall be performed before and during

startup to confirm that the core performance meets the design intent.

Core conditions shall be monitored and the fuelling program shall be

reviewed and modified as necessary.

For fuel and core components, handling procedures shall be written

which include the movement of unirradiated and irradiated fuel, storage

on the site and preparation for dispatch from the site.

Plant operations(6)

Core Management and Fuel Handling

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III. OEF

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Why do we study Operating Experience ?

Can not get similar OE for the plant itself

Can acquire Valuable Lessons from expensive Experiences

Can feedback the collected lessons/inspirations to our facilities

How do we manage valuable Information from the

Operating Experience ?

Collect/ Exchange/ Share domestic & foreign Operating

Experiences

Establish an OEF system for Storage/ Analyze/ Evaluate/ Apply

the OE-related information

OEF Systems [necessity]

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IAEA Convention on Nuclear Safety Article 19 :

Safety significant incidents are reported by the

licensee to the regulatory body

Program to collect and analyze operating experiences

are established

That results obtained and conclusions drawn upon

and

Mechanisms are used to share important experience

between international bodies, other operating

organizations and regulatory bodies

OEF Systems [requirements]

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Safety Fundamentals (No. 110) Principle 21 : Operating organization shall report safety significant

incidents to the regulatory body

Operating organizations and regulatory body shall

establish complementary programs to analyze

operating experience, to ensure lessons are learned

and acted upon;

Such experience shall be shared with relevant

national and international bodies

OEF Systems [requirements]

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National level OEF System

Purpose

Prevent recurring of similar events by management

& incorporating related information and thus

Reduce the potential hazards of events reflecting OE

to the design, operation and maintenance

Related Documents

Convention on Nuclear Safety Article 19. “Operation”

A System for the Feedback of Experience from

Events In Nuclear Installations, NS-G-2.11, 2006

Related Requirement including Reporting (IRS

Guideline)

OEF Systems [RB OEF]

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Collection

Screening

Communication Immediate

Actions

Evaluation / Application

Regulatory Action

Tracking

Storage

Dissemination

• NSSC Notice • IRS, INES • US NRC IN, GL, etc.

• By OE Department • By Technical Groups (9 fields)

• Investigation

• Corrective Actions

• CATS

• Inspections • Safety Reviews

• OPiS • DIOS

- Reference : IAEA Safety Guide No. NS-G-2.11 “A System for the Feedback of Experience from Events in Nuclear Installations”

Overall Program [OEF Process]

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Overall Program [OEF Tools]

IAEA OEF Process Domestic OEF Process Tools

Reporting

Collection

- NSSC Notice 2009-37

- IAEA IRS, Web Site

- USNRC IN, EN, Bulletin etc.

- JNES PRI, etc.

Screening

Immediate Actions Investigation and

Analysis

- KINS Expertism

- e-FAST Investigation

Corrective Actions Corrective Actions - CATS

Trending and

Review

Classification

- Coding System for the Public

- HuRAM

- IAEA IRS

Dissemination and

Review

Dissemination - DIOS

- OPIS

Monitoring of

Effectiveness

Monitoring of

Effectiveness

- Review and Inspection, Audits

- Feedback on Regulatory Activities

and Annual Workshop on OEF QA

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OEF Tools [reporting]

Analysis/ Screening

Event Reporting 1st Investigation

Event review

2nd Investigation

Recommendation Corrective Action

CA Evaluation

Self-Assessment

Fe

ed

bac

k

for S

ys

. Imp

rove

me

nt

Information

Dissemination

Process for the Event Management

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V. OEF Tools

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OPiS [Background]

Background

NPPs and its related facilities are becoming nationally

concerning facilities in Korea.

The Public, NGOs and many Stakeholders want to know safety-related information about NPP and those incidents and failures instantly.

OPiS fulfills these demands, and promotes the public confidence in nuclear safety.

OPiS also implements those functions of the OEF by Disseminating and Storing the information.

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OPiS [Development]

First Version of OPiS Developed in Jan. 2004 for Korean version only

Main contents were NPP Status, NEED, INES and SPI

Became very useful website for the RB and also for many stakeholders

Urged to develop an improved version which could include the English version

Second Version of OPiS Developed in Oct. 2006 for a year

Korean version with English version optional

Improved the functions of NEED, INES and SPI

Includes the abstract of all events in English

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OPiS [Main Pages]

Main Pages NPPs Status

Location of Worldwide NPPs

Specific and Licensing Information about NPPs

NEED (Nuclear Event Evaluation Database)

INES (International Nuclear Event Scale)

SPI (Safety Performance Indicator)

[Website : http://opis.kins.re.kr]

http://opis.kins.re.kr/

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OPiS [NPPs Status]

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OPiS [NEED]

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OPiS [Incident Information]

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OPiS [INES]

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OPiS [INES]

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SPI [Structure]

Area Category Indicator Remark

Reactor

Safety

Operational Safety Unplanned Reactor Scram URS

Unplanned Power Reduction UPR

Multiple Barriers

Fuel Reliability FR

Reactor Coolant Leakage RCL

Containment Reliability CR

Emergency Preparedness EP

Safety System

SIS Availability SI

EDG Availability EDG

AFWS Availability AFW

Radiation

Safety

On-site Rad.

Safety Radiation Collective Dose RCD

Off-site Rad.

Safety Public Dose/Environmental Rad. PD/ER

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OPIS [SPI]

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Effectiveness of OEF

NSSC/KINS are consistently implementing the national OEF

program since 1990’s

Number of Reportable Events is being stabilized and decreased. It

was just 0.35 in 2013 while it was 1.38 in 2001.

Frequency was less than 1.0 during the last 4 years consecutively.

In 2013, the frequency decreased to 0.35 and a value less than 0.5 is anticipated in 2014.

The proper implementation of OEF program is the best and the most positive way to enhance the operational safety and the efficiency of NPPs.

Web-based OEF Tools is necessary and inevitable for the proper

and prompt implementation of the OEF process.

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V. Accidents

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Accidents

3 NPPs have experienced tragic nuclear accidents TMI-2 Accident in March 28,1979

Chernobyl Accident in April 26, 1986

Fukushima Accident in March 11, 2011

A lot of Lessons-Learned and Action Plans were drawn

and have been implemented in all NPP operating

countries to prevent similar accidents and now

Fukushima Action Plans and several Stress Tests are

in progress.

After the TMI-2 Accident, the World Nuclear Society

have recognized, acknowledged and studied the

importance of OEF

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TMI-2 Accident [milestones]

located in Harrisburg in Pennsylvania State of the

USA

Babcock & Wilcox (B&W) designed PWR

thermal power 2,772MWth, electric power 906MWe

milestones 1978.3 first criticality

1978.12.30 commercial operation

1979.3.28 small LOCA thru the PZR PORV occurred

permanent shutdown and decommissioned

1979.7 TMI-2 Lessons Learned Task Force Status Report and

Short-Term Recommendations(NUREG-0578)

1980.11 Clarification of TMI Action Plan Requirements

(NUREG-0737)

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TMI-2 Accident [Plant Overview]

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TMI Accident [Synopsis]

Sequence of Event Condensate Pp stop → Main Feed Water Pp trip → TBN Trip

→ Reactor Trip due to RCS high Pr. → PZR PORV opened but

unidentified → AFW Pp actuated but failed to supply water due to

valve spuriously closed → S/G dryout → ECCS actuated → PRT

Tank rupture disk opened → Block HPSI due to PZR high level →

RCS became saturated state → Cont’t Sump Pp start → Zr-Water

reaction and H2 generated(locally might be H2 explosion) → close

PORV (after 140 min.) → 12 ton of molten corium pool moved to

Reactor Vessel lower head → Core cooling recovery (after 300

min.)

Compounded by the initial mistakes of operators and

human factor problems(MCR indication)

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Results of the TMI-2 Accident

Core melt-down & relocation

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Results of the TMI-2 Accident

Environmental release of Radioactive material • Noble gas 2,500,000 Ci( 5% of noble gas of the core)

• Iodine 15 Ci

Radiation exposure of the publics : negligible

• Collective dose 33 man-Sv

• Average exposure per person: ~0.1mSv(1mrem)

(Max.<100mrem)

[X-ray(~6mrem), natural background dose (~100mrem/yr)]

Increase in Cancer Occurrence : negligible

• Increase 1/50,000 rate (add 1 to 325,000 cancer death )

INES Rating : Level 5

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TMI Action Plans

Short term Action Plan(NUREG-0578) Control Room Design Review

Safety Parameter Display System

Emergency Response Facility

Post Accident Sampling System

Probabilistic Reliability Analysis

Emergency Operating Procedure, etc.

Long term Action Plan(NUREG-0737) Reactor Head Vent valve

H2 Re-combiner, RVLIS, SCMM, ICC

Technical Support Center & Operating Support Center

BE Analysis and revise EOP

Immediate upgrading of RO & SRO training and qualifications

AFW system evaluation

Emergency power for pressurizer heaters

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Action Plan I.A.1.l STA

NRC Position

Each licensee shall provide an on-shift technical advisor to the shift

supervisor.

The shift technical advisor (STA) may serve more than one unit at a

multiunit site if qualified to perform the advisor function for the

various units.

The STA shall have a bachelor's degree or equivalent in a scientific

or engineering discipline and have received specific training in the

response and analysis of the plant for transients and accidents. The

STA shall also receive training in plant design and layout, including

the capabilities of instrumentation and controls in the control room.

The licensee shall assign normal duties to the STAs that pertain to

the engineering aspects of assuring safe operations of the plant,

including the review and evaluation of operating experience.

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Chernobyl Accident

located in Pripyat, Ukraine

designed and built by the former USSR

RBMK-1000 (Boiling Water Reactor

moderated by graphite)

4 Reactors produced about 10 % of

Ukraine’s electricity April 26,1986, Chernobyl disaster

happened.

A level 7 event (the maximum

classification) on the INES.

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RBMK [Reactor]

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RBMK [Plant Overview]

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Chernobyl NPP after the disaster

Chernobyl power plant in 2003 with the sarcophgus

containment structure

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Chernobyl Accident

intended to perform an experiment of bridging power gap

between the Loss of Offsite Power (LOOP) and the full

availability of the Emergency Diesel Generator (EDG)

failed the test 3 times already and 4th time test was

attempted in April 26, 1986 but resulted in a catastrophic

disaster

positive reactivity ( + ρ) was inserted due to the positive

void coefficient (during low reactor power level), extreme

power excursion occurred, and the reactor vessel

ruptured

INES level 7

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NPPs in Japan

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Unit 1

Unit 2

Unit 3

Unit 4

Units 5, 6

At the Time of Earthquake - Reactors 1, 2 and 3 operating - Reactors 4, 5 and 6 shutdown for maintenance, inspection and refueling

Fukushima Daiichi NPPs

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Fukushima NPPs after Disaster

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Fukushima NPPs against Tsunami

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Fukushima Accident [Synopsis]

external hazard induced accident, i.e. earthquake and

tsunami.

the magnitude of historical earthquake or tsunami was

not sufficiently considered in the design stage during

construction.

the volumetric capacity of BWR containment was found

to be inferior to PWR containment during accident.

the importance of ultimate and fundamental bastion and

barrier was realized again and now STRESS TEST to

overcome such things is being implemented. heat sink, emergency electrical power, decay heat

radiation, natural disaster

INES level 7 event

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Fukushima Accident [Chronicle Sequence]

Date Event and Failure Remarks

2011.3.11 14:46 (Friday Afternoon)

- Fukushima-1,2,3 Reactor Trip due to Earthquake

- Unit-1,2,3 experienced Station Black Out(15:40)

- Emergency declared(19:03)

2011.3.12 - Unit-1 Hydrogen explosion(15:36)

- Sea Water to Unit-1 Reactor

1st H2 explosion

2011.3.14

- Unit-3 Hydrogen explosion(11:01)

- Sea Water to Unit-2 Reactor

2nd H2 explosion

2011.3.15

- Unit-2 Containment failure and large radiation

release to environment

- Unit-4 Hydrogen explosion(06:10)

3rd H2 explosion

SFP suspicious

2011.3.16 - Rad. Level increased to 1,000mSv/h temporarily

2011.3.17~19 - Unit-5,6 recovered RHR System Operability

2011.3.20~31 - Units recovered Offsite Power

- Fresh Water injected to all Units

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Thank you for your attention! شكرا